Loading among the phases in a poly-phase electrical system is not always balanced because all loads attached to the poly-phase system are not connected to all of the phases. For example, in a three-phase electrical system serving a multi-story facility, one phase (e.g., A phase) may serve the first floor, while another phase (e.g., B phase) may serve the second floor and a third phase (e.g., C phase) may serve the third floor. Loads on the three floors may not be balanced—some floors may have no loads at all (e.g., the floor is not finished or it has not been leased). In other instances, loads may only be connected to a subset of the number of phases available. For example, in a three phase system, some of the loads may only be connected to two of the three phases rather than all three phases. This can also cause load imbalance.
Imbalanced loads can cause excessive voltage drop on the phase (or phases) that are more heavily loaded due to higher I2R losses in those phases. Imbalance can also result in higher than normal neutral currents, unexpected heating in electrical power delivery systems and devices and harmonics on the power system. Therefore, it is desired that loads be as balanced as practicable in poly-phase electrical systems.
In some instances, utility providers desire to electronically communicate with the utility service meters serving the loads for numerous purposes including scheduling disconnection or connection of utility services to the metered loads, automatic meter reading (AMR), load shedding and load control, automatic distribution and smart-grid applications, outage reporting, providing additional services such as Internet, video, and audio, etc. In many of these instances, to perform these functions the meters can be configured to communicate with one or more computing devices through a communications network, which can be wired, wireless or a combination of wired and wireless, as known to one of ordinary skill in the art.
In many instances, such meters are also equipped with one or more electromechanical switches that can be actuated either locally by an on-board processor or remotely to perform functions such as disconnection or connection of utility services to the metered loads, load shedding and load control, and the like.
Therefore, systems and methods are desired that can help balance loads on an electrical system including phase enablement or disablement in a smart meter to overcome challenges present in the art, some of which are described above.